The concept of the rotary-vane machine (RVM) has been known for a long time, and continues to attract attention due to a number of advantages it has over machines utilizing reciprocating piston motion. Some of the advantages of the RVM are: mechanical simplicity, fewer parts, time-independent lever arm for gas pressure forces, and easier compensation of forces that act to bend the shafts.
There is reason to assert that in the RVM conditions for complete combustion of fuel are better observed, making the machine environmentally cleaner when compared with conventional piston engines. According to the Le Chatelier-Braun principle, the process of fuel combustion in a confined volume that releases heat and increases pressure is stimulated by an increase in volume, as an increase in volume causes pressure to decrease. In the RVM, the volume of the power stroke chamber increases at a greater rate than in a comparable reciprocating piston machine. This fact inspires confidence that the combustion of fuel in a RVM will be more complete, and hence that operation of the RVM will bring less harm to the natural environment.
There have been numerous attempts to build RVMs, and there exist a large number of patents of various designs, however, to this day, not one of the many proposed constructions has been successful in practical testing.
In a RVM, to realize the cycles of internal combustion it is necessary to ensure coordinated rotation of the shafts. The main cause of failure in all known and proposed variants of RVM construction is that they employ mechanical linkages to coordinate shaft rotation; none of the proposed variants are sufficiently reliable and capable of long-term operation. Components in these mechanical linkages experience alternating shock loadings, which quickly lead to their destruction, and consequently inoperability of the RVM.
An example of a known rotary vane engine invention is patent RU2237817, which proposes attaching reversible electrical machines (REM) onto the shafts of the engine, but, to keep the trailing vane from rotating backwards, proposes a mechanical linkage (a locking device or ratchet) which makes the device practically unusable due to unavoidable quick wear and tear of this mechanical part. Other designs, for example WO 2008/081212 A1, also propose to install REMs onto shafts, and also propose mechanical stopper devices to ensure motion of the rotor in one direction only.